Semiconductor light-emitting device

ABSTRACT

Disclosed is a semiconductor light emitting device comprising a semiconductor light emitting chip having electrodes; a mold, which has a first surface roughness and includes a bottom portion where the semiconductor light emitting chip is arranged and through holes formed in the bottom portion, with the through holes being comprised of a surface having a second surface roughness different from the first surface roughness, wherein at least one side of the mold facing the semiconductor light emitting chip is made of a material capable of reflecting at least 95% of light emitted by the semiconductor light emitting chip; and conductive parts provided in the through holes for electrical communication with the electrodes.

TECHNICAL FIELD

The present disclosure relates generally to a semiconductor lightemitting device, and more particularly to a semiconductor UV lightemitting device.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

FIG. 1 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 9,773,950. In particular, itpresents a CSP (Chip-Scaled Package) semiconductor light emittingdevice. The CSP semiconductor light emitting device includes asemiconductor light emitting chip 2, an encapsulating member 4, and areflector 6 (e.g., a white photo solder resist(PSR)). The semiconductorlight emitting chip 2 includes electrodes 80 and 90. The encapsulatingmember 4 has slanted sides 4 b to adjust an emission angle of light fromthe semiconductor light emitting chip 2. The reflector 6 may be obtainedby screen printing or spin coating a white PSR, followed by patterningwith a typical photolithography process. If required for externalelectrical connection, external electrodes 81 and 91 may be providedthrough a deposition process.

FIG. 2 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 10,008,648. In particular, itpresents a semiconductor light emitting device 200 employing apre-formed, rigid frame or mold 210 (e.g., injection molded frame) inorder to maintain the positioning accuracy of a semiconductor lightemitting chip 2 through a series of processes, which otherwise could bedeteriorated due to the reflector 6 (e.g., the white PSR) of FIG. 1 madeof flexible materials. As shown in FIG. 2, the semiconductor lightemitting device 200 is provided with a mold 210, a semiconductor lightemitting chip 220, and an encapsulating member 230. Other parts of thedevice 200 shown in the drawing include side walls 211, a bottom portion212, a hole 213, a cavity 214, an upper face 215 of the bottom portion212, a lower face 216 of the bottom portion 212, outer faces 217 of theside walls 212, inner faces 218 of the side walls 211, an electrode 221,a light converting material (phosphor) 231, and side walls 240 of thehole 213, with the bottom portion 212 having a height 219, the sidewalls 211 having a height H, and the semiconductor light emitting chip220 having a height 222. This semiconductor light emitting device 200 issimilar to a surface-mounted device (SMD) type semiconductor lightemitting device (see U.S. Pat. No. 6,066,861) in that it has a mold 210,the absence of a lead frame or lead electrode, however, resolves theabove-mentioned issue of the semiconductor light emitting device in FIG.1, and also prevents any problem that involves bonding with an externalsubstrate (e.g., cracks).

FIG. 3 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in Korean Patent Application Laid-Open No.10-2018-0131303. The semiconductor light emitting device is also freefrom the issue associated with the reflector 6 of FIG. 1 and includes amold 113 and a semiconductor light emitting chip 123. The mold 113 hasconductive parts TH1 and TH2 made of a conductive paste or solderingmaterials. Other parts of the device shown in the drawing include acavity C, electrodes 121 and 122, and an external substrate 131 (e.g., aPCB or a sub-mount). This semiconductor light emitting device is similarto the one shown in FIG. 2 in that it does not have a lead frame or leadelectrode, the conductive parts TH1 and TH2, however, are involved inphysical and electrical junction between the external substrate 131 andthe semiconductor light emitting chip 123 and may even be separated fromthe mold 113 due to poor connection if the physical bonding strengthgets weaker during the SMT process, as discussed in FIG. 2. On one hand,the semiconductor light emitting device illustrated in FIG. 2 is builtwithout a lead frame or lead electrode such that it can suitably preventlight absorption by the lead frame or lead electrode. On the other hand,the semiconductor light emitting device illustrated in FIG. 3 is adaptedto practically block light leaks downward of the mold 113 and to allowall the light generated by the semiconductor light emitting chip 123 tobe emitted upward.

To summarize how an LED package has been developed or evolved, a lateralchip had first been wire-bonded to an SMD-type package, and a flip chipwas then introduced to satisfy the demand for a high-power andhigh-voltage device. Later, it turned out that the flip chip was alsoinadequate for the SMD-type package, encouraging the use of a CSP-typepackage as shown in FIG. 1. As discussed earlier, however, this alsoimposed some challenges in adjustment of a beam angle and issues in amanufacturing process. Nowadays, a leadless frame or mold-type LEDpackage without a lead frame or lead electrode, as shown in FIGS. 2 and3, is being used. However, in case of the semiconductor light emittingdevice in FIG. 3, holes are formed in the mold 113 (e.g., injectionmold) for the conductive parts TH1 and TH2, respectively. Theseinjection molded holes have a smooth surface corresponding to thesurface roughness of the mold. Therefore, the physical bonding strengthbetween the mold and the conductive parts TH1 and TH2 (prepared bydeposition or plating) may not be high enough to hold them together.

Objectives, advantages, and a preferred mode of making and using theclaimed subject matter may be understood best by reference to theaccompanying drawings in conjunction with the following detaileddescription of illustrative embodiments.

SUMMARY

This section provides a general summary of the disclosure and is not acomprehensive disclosure of its full scope or all of its features.

According to one aspect of the present disclosure, there is provided asemiconductor light emitting device, comprising: a semiconductor lightemitting chip having electrodes; a mold, which has a first surfaceroughness and includes a bottom portion where the semiconductor lightemitting chip is arranged and through holes formed in the bottomportion, with the through holes being comprised of a surface having asecond surface roughness different from the first surface roughness,wherein at least one side of the mold facing the semiconductor lightemitting chip is made of a material capable of reflecting at least 95%of light emitted by the semiconductor light emitting chip; andconductive parts provided in the through holes for electricalcommunication with the electrodes.

According to another aspect of the present disclosure, there is provideda method for manufacturing a semiconductor light emitting deviceincluding a semiconductor light emitting chip having electrodes, a moldwhich has a bottom portion where the semiconductor light emitting chipis arranged and through holes formed in the bottom portion, andconductive parts provided in the through holes for electricalcommunication with the electrodes, the method comprising: preparing alead frame which has one or more molds and an anti-plating layer formedon a region exposed from the molds; forming conductive parts in each ofthe molds and electrically communicating the conductive parts with theelectrodes of the semiconductor light emitting chip; and cutting out thelead frame to obtain individual semiconductor light emitting devices.

According to another aspect of the present disclosure, there is provideda semiconductor light emitting device, comprising: a semiconductor UVlight emitting chip having electrodes; a bottom portion where thesemiconductor light emitting chip is arranged, with the bottom portionbeing made of a ceramic material and including conductive parts forelectrical communication with the electrodes; and a reflective walldefining a cavity to accommodate the semiconductor light emitting chiptherein, with the reflective wall being made of a non-metal andincluding a slanted side that reflects UV light and a metal reflectivelayer formed on the slanted side.

According to another aspect of the present disclosure, there is provideda semiconductor light emitting device adapted to be coupled to a powersupply board by a solder, comprising: a semiconductor light emittingchip having electrodes; a mold, which includes a bottom portion wherethe semiconductor light emitting chip is arranged and through holeshaving a surface roughness higher than that of an upper side of thebottom portion; hollow conductive parts provided in the through holesfor electrical communication with the electrodes; and an airgap-preventing material provided in each of the through holes forpreventing the creation of air gaps as the solder enters into thethrough holes along the conductive parts.

Objectives, advantages, and a preferred mode of making and using theclaimed subject matter may be understood best by reference to theaccompanying drawings in conjunction with the following detaileddescription of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 9,773,950.

FIG. 2 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 10,008,648.

FIG. 3 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in Korean Patent Application Laid-Open No.10-2018-0131303.

FIG. 4 illustrates an exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 5 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 6 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 7 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 8 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 9 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure.

FIG. 10 illustrates an individual type of lead frame and molds describedin U.S. Patent Application Publication No. 2014/0054078.

FIG. 11 shows a method for manufacturing a semiconductor light emittingdevice according to the present disclosure.

FIG. 12 illustrates another exemplary embodiment of a semiconductorlight emitting device according to the present disclosure.

FIG. 13 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Patent Application Publication No.2014/0367718.

FIG. 14 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 8,106,584.

FIG. 15 illustrates another exemplary embodiment of a semiconductorlight emitting device according to the present disclosure.

FIGS. 16 and 17 illustrate another exemplary embodiment of asemiconductor light emitting device according to the present disclosure.

FIG. 18 is a plot of reflectance vs wavelength for different metals.

DETAILED DESCRIPTION

One of the features of the present disclosure is a through hole formedat the bottom portion of a mold for a semiconductor light emittingdevice that has a higher roughness on the inner surface of the hole toimprove bonding strength between the mold and an electroless platedconductive material. The through hole is either laser drilled orpre-formed during injection molding. Although the thickness of thebottom portion of the mold is not particularly limited, it preferablyranges from 100 to 500 μm. For example, the thickness is preferably 100μm or more such that the light generated by a semiconductor lightemitting chip may not be transmitted downward and a sufficiently largearea of the mold is bonded with the electroless plated conductivematerial. In addition, the thickness is preferably 500 μm or lower tomake laser drilling possible. Needless to say, if the mold has a verythick bottom portion, laser irradiation will have to be carried outmultiple times.

A second feature of the present disclosure is a material of the moldthat contains laser direct structuring (LDS) additives in addition tothermoplastics or thermosetting plastics. In application of the LDSprocess, the surface of an injection molded article made of a moldingresin is subjected to laser irradiation, followed by electrolessplating. The former results in a rougher and electrically activatedsurface, and the latter allows the formation of a conductive materialthereon. Examples of a molding resin typically used for a semiconductorlight emitting device include thermoplastics such as polyphthalamide(PPA) or polycyclohexylene dimethylene terephthalate (PCT)), andthermosetting plastics such as epoxy mold compounds (EMC) or siliconemolding compounds (SMC). When blue or green light emitting chips areused, the molding resin is added with a filler or a light scatteringagent to increase the reflectance, including, for example, but withoutlimitation, a white pigment TiO₂ (titania), SiO₂ (silica) and/or Al₂O₃(alumina). In addition to the PPA and PCT mentioned above, otherthermoplastics may also be used for a light emitting device, including,for example, but without limitation, polyamides (PA), polycarbonate(PC), polyphthalamide (PPA), polyphenylene oxide (PPO), polybutyleneterephthalate (PBT), cycloolefin polymers (COP), liquid-crystal polymers(LCP), copolymers or blends thereof, such asacrylonitrile-butadiene-styrene/polycarbonate blend (PC/ABS), PBT/PET,and the like. Likewise, in addition to the EMC and SMC mentioned above,other thermosetting plastics may also be used for a light emittingdevice, including, for example, but without limitation, polyurethanes,melamine resins, phenolic resins, polyesters, and epoxy resins. However,successful implementation of a leadless frame or a mold-type LED packageincluding a flip-chip type semiconductor LED chip is achieved by the LDSprocess, forming an electrical conductor circuit pattern (conductivematerial) with a strong physical bonding strength on the surface of theinjection molded article made of a molding resin. In general, LDStechnology is widely known and has been in the spotlight in thefast-growing mobile phone industry for its capability of directimplementation of an electrical conductor circuit pattern (conductivematerial) that serves as an antenna, onto the surface of a 2D and/or 3Dinjection molded article made of a molding resin. Its illustration canbe found in an article titled “Selective Metallization Induced by LaserActivation: Fabricating Metallized Patterns on Polymer via Metal OxideComposite”, ACS Appl. Mater. Interfaces 2017, Volume 9, Pages 8996-9005.As described in this article, 5 wt. % of CuO.Cr₂O₃ (Cu—Cr oxidecomposite) is blended with an ABS polymer matrix and the resultingmixture is injection molded. When a 1064 nm laser beam is irradiatedonto the surface of the injection molded article, CuO.Cr₂O₃ isdecomposed and a significant amount of electrically activated metallicCu radicals are formed on a roughened surface, and the radials serve asseeds in the subsequent electroless plating process. In particular, itis possible to form micro electric path lines having a 100-micron (μm)resolution by optimizing certain parameters of the laser beam beingirradiated (i.e., wavelength=1064 nm, power output=8W, irradiationspeed=2000 mm/s). The plating process can be carried out on the surfaceof the injection molded article made of a molding resin because themolding resin is ablated by laser irradiation, resulting in a roughenedsurface, and the LDS additives anchored in the surface are thenelectrically activated and serve as seeds for forming an electrolessplated layer. Among others, the LDS additives serving as seeds in themolding resin (e.g., the thermosetting plastic or thermoplastic) by theirradiated laser beam during the LDS process is referred to as a firstadditive. Additionally, or alternatively, other functional additives maybe mixed with the first additive to meet the requirements of a device interms of improving heat dissipation or increasing the opticalreflectance, for example. In general, the first additive may include atleast one of: Pd-based heavy metal complexes and metal oxides, metaloxide-coated fillers, CuO.Cr₂O₃ spinel, copper salts, copperhydroxyphosphate, copper phosphate, cuprous thiocyanate, spinel-basedmetal oxides, CuO.Cr₂O₃, organometallic complexes, antimony (Sb) dopedSn oxide, or metal oxides containing Cu, Zn, Sn, Mg, Al, Au, Ag, Ni, Cr,Fe, V, Co, or Mn. To improve heat dissipation performance, a secondadditive may be added as another functional additive. The secondadditive may include at least one of: AlN, AlC, Al₂O₃, AlON, BN, MgSiN₂,Si₃N₄, SiC, graphite, graphene, carbon fiber, ZnO, CaO, or MgO. Toimprove the optical reflectance, a third additive may be added asanother functional additive. The third additive may include at least oneof: TiO₂, ZnO, BaS, or CaCO₃. The type of molding resins and LDSadditives used and mixing ratios thereof may vary depending on the usageof an applied current to a semiconductor light emitting device. Sincethe first additive used as a primary component for the LDS process andthe second additive used for improving heat dissipation are typicallynot involved in light reflection, they are used to a very limited extent(e.g., 10 wt. % or less). This can be different whether the additivesare used for semiconductor light emitting devices or for general MIDs(Mold Interconnect Devices). Again, the type of molding resins and LDSadditives and mixing ratios thereof may vary depending on the usage ofan applied current to a semiconductor light emitting device. As analternative, the mold can be injection molded in the form of a singlepart or separated parts, in which an amount of the first and secondadditives used in the bottom portion of the mold may be relativelylarger than an amount of the first and second additives used in theother portions of the mold. If the LDS additives (the first, second andthird additives) are used to a very limited extent, certain parametersof the laser beam being irradiated (e.g., wavelength, power output, andirradiation speed) may be modified according to the type of the LDSadditives such that desired performance can be achieved. For example,although fiber laser (e.g., a 1064 nm wavelength laser beam for markingthe plastic laser surface) is generally used during the LDS process, alaser beam having a UV wavelength band (400 nm or less) may have to beirradiated for a lengthier amount of time if a higher energy source isneeded to decompose and activate the additives, such as, AlN (the secondadditive) and TiO₂ (the third additive). For instance, the thirdadditive TiO₂ is present in the molding resin in an amount of at least50 wt. % such that the molding resin may reflect at least 95% of thelight generated by the semiconductor light emitting chip. During theinjection molding, a laser beam with an appropriate wavelength (308 nmxenon chloride excimer laser) and power output or a laser beam used fordrilling is irradiated onto the mold having a pre-formed through hole,and TiO₂ is decomposed to metal Ti radicals+ionic TiO_(x) radicals+½ O₂gas, which are then electrically activated (Ti and TiO_(x)), serving asseeds for the subsequent electroless plating.

A third feature of the present disclosure is an additional metaltreatment applied to a lower surface of the bottom portion of the moldfor better heat dissipation and increased physical bonding strength withan external substrate. That is, the electroless plating layer formed inthe through hole is electrically connected to a metal to provide anelectrical connection with the external substrate. If needed for anelectrical connection to a semiconductor light emitting chip, this metaltreatment may also be applied to an upper surface of the bottom portionof the mold, electrically connecting a metal to the electroless platinglayer formed in the through hole.

The present disclosure will now be described in detail with reference tothe accompanying drawing(s).

FIG. 4 illustrates an exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. As shown in FIG.4A, the semiconductor light emitting device includes a semiconductorlight emitting chip 11 and a mold 14. The semiconductor light emittingchip 11 is surrounded with an encapsulating member 31 that contains alight converting material such as a phosphor. The semiconductor lightemitting chip 11 has electrodes 12 and 13. If a flip chip is used, agrowth substrate 11 a may be provided on opposite sides of theelectrodes 12 and 13. This growth substrate 11 a may be removed later.In general, the mold 14 has a bottom portion 15 where the semiconductorlight emitting chip 11 is arranged, and a reflective wall 14 a foradjustment of a beam angle. The mold 14 is usually pre-formed (e.g.,injection molded), and its surface has a roughness determined by themold. The bottom portion 15 has an upper side 15 a and a lower side 15b, and through holes 16 and 17 are formed, passing through the upperside 15 a and the lower side 15 b. While the through holes 16 and 17 arepreferably pre-formed by the mold, they can also be formed by laserdrilling. The mold 14 is prepared by blending ingredients, including,for example, a resin (e.g., PPA, PCT, EMC, or SMC) and a white,light-reflecting filler (e.g., the third additive TiO₂) in a mixingratio that allows the mold 14 to reflect at least 95% of the lightgenerated by the semiconductor light emitting chip 11 to reduce lightabsorption. Additionally, or alternatively, instead of having the entiremold 14 made of the material described above, only those sides facingthe semiconductor light emitting chip 11 may be coated with the material(see FIG. 9). The through holes 16 and 17 have conductive parts 18 and19, respectively. The through holes 16 and 17 have a roughened surfaceso that the conductive parts 18 and 19 can be anchored thereon. The term“roughened” used herein means that the surface of the through holes 16and 17 is processed, e.g., ablated by laser beam irradiation or laserdrilling, so that the conductive parts 18 and 19 can be anchoredthereon. If the through holes 16 and 17 are formed together with themold 14, the through holes 16 and 17 and the mold 14 would have the samesurface roughness. If the mold 14 contains metals and the first, secondand/or third LDS additives (TiO₂, CuO, Cu₂O, NiO, Cr₂O₃, PdO, Al₂O₃)composed of non-conductive materials having ionic radicals, the metalsare activated once the pre-formed or laser drilled through holes 16 and17 in the mold 14 are exposed to the laser beam and serve as seeds forforming the conductive parts. In this case, the conductive parts can beformed without a separate patterning process, but by electroless platingonly in the region activated by the laser. Additionally, a heatdissipation metal layer 21 may be formed by irradiating the laser beamonto the lower side 15 b of the bottom portion and activating the metalcontained therein. Preferably, the heat dissipation metal layer 21 isconnected to the conductive parts 18 and 19. Similarly, forming the heatdissipation layer 21 by electroless plating makes it easier to form theheat dissipation layer 21 following a pattern of laser beam irradiation,that is, based on the designed pattern. For instance, the mold 14 may beprepared by blending 3 wt. % of CuO.Al₂O₃ or CuAl₂O₃ with a PCT polymermatrix, and the resulting blend is subjected to injection molding. Next,through holes 16 and 17 having a diameter of 300 microns and a depth of250 microns are formed in the mold. Additionally, or alternatively,after the laser beam is irradiated, a process of removing residues canbe carried out. In this manner, Cu (10 μm)/Ni (1 μm)/Au (0.02 μm) aresequentially formed by electroless plating.

A conductive paste (e.g., Ag, Cu), a soldering material (e.g., SAC),etc. may be employed for bonding of the semiconductor light emittingchip 11 and the conductive parts 18 and 19, as in the prior art, and anon-conductive adhesive {circle around (1)} (e.g., a silicone adhesive)may be applied to multiple regions to ensure physical bonding betweenthe chip and the conductive parts. Additionally, or alternatively, thesemiconductor light emitting chip 11 may be physically attached to themold 14 using the non-conductive paste only, and later, to the externalsubstrate 131 (see FIG. 3) by introducing a conductive paste or asoldering material into the partially filled through holes 16 and 17 toensure the electrical connection with the external substrate. FIG. 4Bshows a top view of the semiconductor light emitting device, in whichthe hollow, circular conductive parts 18 and 19 are combined with thecircular electrodes 12 and 13.

FIG. 5 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. Here, the upperside 15 a of the bottom portion 15 is also laser ablated as shown inFIG. 5A, such that upper metal layers 18 a and 19 a have a laser ablateddesign pattern. The conductive parts 18 and 19, the heat dissipationmetal layer 21, and the upper metal layers 18 a and 19 a can be formedall together during electroless plating. Further, in addition to thenon-conductive adhesive {circle around (1)}, a conductive adhesive{circle around (2)} (e.g., a soldering material) may be employed forbonding of the upper metal layers 18 a and 19 a and the electrodes 12and 13. In doing so, stable electrical/physical bonding is secured evenbefore the semiconductor light emitting device is connected to theexternal substrate 131 (see FIG. 3). This stability was demonstrated ina reliability test. Referring to FIG. 5B, the upper metal layers 18 aand 19 a may be formed smaller than the electrodes 12 and 13 to causelight absorption by the upper metal layers 18 a and 19 a to be reduced.

FIG. 6 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. Here, the throughholes 16 and 17 are filled with the conductive parts 18 and 19, as shownin FIG. 6A. The conductive adhesive {circle around (2)} is employed forbonding of the conductive parts 18 and 19 and the electrodes 12 and 13.Filling can be achieved by electroless plating, or by heat treatmentwhere a conductive paste material containing a high-temperature solder,Ag and Cu is treated at a temperature of 250° C. or higher. Theelectroless plating process is preferred. Unlike the semiconductor lightemitting device illustrated in FIG. 4, the through holes 16 and 17 inthis semiconductor light emitting device are filled, providing improvedheat dissipation performance and increased bonding strength with anexternal substrate, although it might take some time to fill the throughholes 16 and 17.

In an implementation of the semiconductor light emitting devicesillustrated in FIGS. 4-6, the first additive used as a primary componentin the LDS process and/or the second additive used to improve heatdissipation performance are preferably added to the mold 14 to a verylimited extent (e.g., 10 wt. % or less) since they are typically notinvolved in light reflection. In other words, although these additivesare optimized for the LDS process, their reflectance is not high. Toresolve this problem, therefore, a nanoscale (nano-dimensioned) particlematerial can be added to the mold 14 that can be activated on its own orby laser irradiation and serve as seeds for plating, while showing a lowabsorption and high transparency for visible light. Examples of such ananoscale (nano-dimensioned) particle material may include, but withoutlimitation, metals (e.g., Ag) and metal oxides (e.g., Al₂O₃, SiO₂, TiO₂,SnO₂, In₂O₃, ITO, ZrO₂, ZnO, CeO₂, Ta₂O₅). For example, the mold 14 maybe formed using a blend of PCT with a certain amount of ZnO andnanoscale Ag particles.

FIG. 7 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. Here, thereflective wall 14 a and bottom portion 15 of the mold 14 are made ofdifferent materials. That is, the reflective wall 14 a contains themolding resin, TiO₂ for light reflection, and SiO₂ or Al₂O₃ as a lightscattering (or diffusing) agent. Meanwhile, the bottom portion 15contains the first and second LDS additives (e.g., Cu₂O, NiO, Cr₂O₃, PdOor other LDS additives) for light absorption. These materials can bepresent in any combination of at least two, or a sequentially varyingcombination. Such composition is particularly useful if the mold 14contains LDS additives. Thus, the mold 14 can be molded by injectingthese molding materials in a sequentially varying combination, or byinjecting different molding materials into an upper mold correspondingto the reflective wall 14 a and a lower mold corresponding to the bottomportion 15.

FIG. 8 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. Here, thereflective wall 14 a and bottom portion 15 of the mold 14 are not onlymade of different materials, but they are also bonded with an adhesive14 b, instead of being molded all at once in a body.

In an implementation of the semiconductor light emitting devicesillustrated in FIGS. 7-8, the bottom portion 15 of the mold 14 and thereflective wall 14 a of the mold 14 may be injection molded in the formof a single part or separated parts, in which an amount of the first andsecond additives contained in the bottom portion 15 of the mold 14 isrelatively larger than the amount of the first and second additivescontained in the reflective wall 14 a.

FIG. 9 illustrates another exemplary embodiment of a semiconductor lightemitting device according to the present disclosure. Here, the mold 14includes a matrix 14 c of a material capable of reflecting at least 95%of the light generated by the semiconductor light emitting chip 11(e.g., a polymer used in LDS), and a reflective layer 14 d coated on thematrix. The reflective layer 14 d may include, for example, Ag, Cr/Ag,Cu/Ag, Al, Cr/Al, Cu/Al, Au, Cr/Au, Cu/Ni/Au, DBR, White resin, or PSR.A recessed space called a cavity 41 is defined by the reflective wall 14a and the bottom portion 15, and the reflective layer 14 d is formedinside the cavity 41 of the mold 14. A material suitable for drillingand plating and a material suitable for light reflection may be combinedto form the mold 14.

FIG. 10 illustrates an individual type of lead frame 50 and molds 25described in U.S. Patent Application Publication No. 2014/0054078, inwhich each of the molds 25 is formed independently with at least oneside being separated from each other. Alternatively, though theexemplary embodiments described above are not provided with a lead frameor lead electrode and therefore there is no electrical connectionbetween the lead frame or lead electrode and the semiconductor lightemitting chip 11 (see FIG. 4), the lead frame or lead electrode 50 maypass through the molds 25, detouring or deflecting the bottom portion 35thereof (e.g., U.S. Pat. No. 10,008,648). For mass production, it ispreferred that multiple molds 25 are formed across the lead frame 50.

FIG. 11 shows a method for manufacturing a semiconductor light emittingdevice according to the present disclosure, and two semiconductor lightemitting devices 100 a and 100 b are presented for convenience ofdescription. As shown, the mold 14 of each semiconductor light emittingdevice 100 a or 100 b is integrally formed with the lead frame 50, andan anti-plating layer 51 is formed on a region of the lead frame 50 thatis exposed from the mold 14. The presence of the anti-plating layer 51on the exposed region of the lead frame 50 allows to stably form aplating layer on other parts, namely, each of the conductive parts 18and 19, the upper metal layers 18 a and 19 a and/or the heat dissipationmetal layer 21. Except that the anti-plating layer 51 is formed on theexposed region of the lead frame 50 from the mold 14, the exemplaryembodiments illustrated in FIGS. 4-9 are manufactured, undergoing thesame subsequent processes. In due course, the exposed region of the leadframe 50 is cut out and an individual semiconductor light emittingdevice is obtained. Additionally, or alternatively, the anti-platinglayer 51 may be formed on the entire lead frame 50, and the multiplemolds 14 may be integrally formed with the lead frame 50 by injectionmolding, for example. Moreover, having the anti-plating layer 51 on theexposed region of the lead frame 50 from the mold 14 does notnecessarily exclude the possibility of having an electrical connectionbetween the lead frame 50 and the semiconductor light emitting chip 11.The anti-plating layer 51 can be obtained by coating of an insulatinglayer, for example. If the mold 14 is not coated with the insulatinglayer, an electrical insulating layer may be provided byelectro-deposition coating. On the other hand, if the mold 14 needs tobe coated, e.g., with an insulating material, it can be done with anysuitable method. For example, when the mold 14 is black, the lead frame50 including the mold may be coated with a white insulating material inorder to increase the reflectance of the semiconductor light emittingchip 11.

Further, according to the present disclosure, any material showing a lowabsorption and high transparency for visible light, e.g., a nanoscale(nano-dimensioned) particle material including, but without limitation,metals (e.g., Ag) or metal oxides (e.g., Al₂O₃, SiO₂, TiO₂, SnO₂, In₂O₃,ITO, ZrO₂, ZnO, CeO₂, or Ta₂O₅) may be added additionally, oralternatively, to the first, second and/or third additives. Therefore,the problems due to the usage of an additive optimized for LDS buthaving a lower transparency may be resolved by providing the mold 14with a material that has a high transparency and can possibly beactivated on its own or by laser irradiation to serve as a seed forplating. For example, the mold 14 may be formed using a blend of PCTwith a certain amount of ZnO and nanoscale Ag particles.

FIG. 12 illustrates another exemplary embodiment of a semiconductorlight emitting device according to the present disclosure. Thissemiconductor UV light emitting device incorporates the technical ideaof the disclosure. As shown, the semiconductor light emitting deviceincludes a semiconductor light emitting chip 11 and a body 14 e.Preferably, it has a window 60 (e.g., quartz, sapphire). Thesemiconductor light emitting chip 11 emits UV light. Generally, UV lightis categorized into UVA (400-315 nm), UVB (315-280 nm), and UVC (280-100nm), depending on its wavelength. The body 14 e has a reflective wall 14f and a bottom portion 15 a, together defining a cavity 41. Thereflective wall 14 f has a reflective layer 14 g. Unlike in the case ofprevious exemplary embodiments, the bottom portion 15 a is comprised ofa single crystal sapphire substrate or a ceramic substrate of sinteredAlN, Al₂O₃ or SiN_(x). The bottom portion 15 a includes conductive parts18 and 19. If needed, it may further include a heat dissipation metallayer 21 a. One example of the bottom portion 15 a is described in U.S.Patent Application Publication No. 2017-0317230. The reflective layer 14g is formed by applying the LDS process to the reflective wall 14 f.Given that the LDS process can be carried out, the reflective wall 14 fmay have any shape without particular limitations, independently of thereflectance for the light generated by the semiconductor light emittingchip 11. It is understood that white resins such as PPA, PCT, EMC, SMC,etc. conventionally used for infrared and visible lights are not alwayssimple to use or suitable for UV light of shorter wavelengths. Accordingto the present disclosure, the reflective wall 14 f may be made of anymaterial suitable for the LDS process, while the reflective layer 14 gmay be made of a material selected depending on wavelength of the lightgenerated by the semiconductor light emitting chip 11 (e.g., Ag for UVA,and Al for UVB and UVC). As mentioned in FIG. 9 above, additionally, oralternatively, a sequentially varying combination of highly adhesivemetals (e.g., Cu, Cr, Ni) and highly reflective metals (e.g., Ag, Al)may also be employed. Examples thereof include, but without limitation,Ag, Cu/Ni/Au/Ag, Cu/Ni/Sn/Ag, Cr/Ag, Cu/Sn/Ag, Al, Cu/Ni/Al,Cu/Ni/Sn/Al, Cr/Al, or Cu/Sn/Al.

If the bottom portion 15 a is comprised of a ceramic substrate, thereflective wall 14 f and the reflective layer 14 g are generallyprepared in two processes. To improve structural stability, opticalperformance and quality with reduced manufacturing cost, additionalprocesses may be added, or the processes can be carried out in adifferent order. A certain outer edge section of the bottom portion 15 ahaving the conductive parts 18 and 19 and a surface reflective layer(not shown) can be bonded to the reflective wall 14 f, without using aseparate bonding layer 14 b (this is called an integration process).Alternatively, the bottom portion 15 a can be bonded to the reflectivewall 14 f, using a separate bonding layer 14 b (this is called a hybridprocess). In case of the integration process, the reflective wall 14 fand the bottom portion 15 a are integrated (i.e., the reflective wall 14f is injection molded to the bottom portion 15 a), and a laser beam isirradiated onto the reflective wall 14 f including its slanted side 14f-1 as well as its upper side 14 f-3 and/or stepped sides 14 f-21 and 14f-22 (see FIG. 15) to activate and make them serve as seeds forelectroless plating. In case of the hybrid process, however, the bottomportion 15 a and the reflective wall 14 f are separately prepared, andlaser beam irradiation and electroless plating are consecutively carriedout on a lower side 14 f-2 of the reflective wall 14 f before thebonding layer 14 b is introduced to put the reflective wall and thebottom portion together. Although the hybrid process has an extraintegrating step compared with the integration process, it is expectedthat the hybrid process would provide strong bonding. Additionally, oralternatively, in the hybrid process, not only the lower side 14 f-2 ofthe reflective wall 14 f, but the slanted side 14 f-1, upper side 14f-3, and/or stepped sides 14 f-21 and 14 f-22 of the reflective wall 14f may also be subjected to the laser beam irradiation all at once to beactivated for electroless plating. In an alternative, after electrolessplating (e.g., Cu/Ni/Sn) is carried out on the slanted side 14 f-1 ofthe reflective wall 14 f as well as on the upper side 14 f-3 and/orstepped sides 14 f-21 and 14 f-22 of the reflective wall 14 f, Al or Agcan be deposited by a PVD process to form the reflective layer 14 g. Inanother alternative, the reflective wall 14 f may be plated with a metalsuitable for LDS (e.g., Cu or Cu/Ni), and then electroplated with Snbecause Sn has an excellent reflectance of 0.7 or higher even in the UVregion and demonstrates excellent bonding strength when combined withthe bonding layer 14 b, as illustrated in FIG. 18. If applied directlyonto Cu, Sn can also contribute to prevent oxidation of Cu.Additionally, or alternatively, (i) after Sn is electroplated, a metalhaving a higher reflectance than Sn (e.g., Al, Rh, or Ag) may be addedto form the reflective layer 14 g, in the form of, for example, butwithout limitation, electroplated Cu/electroplated Sn/Al, electroplatedCu/electroplated Sn/Rh, electroplated Cu/electroplated Sn/Ag,electroplated Cu/electroplated Ni/electroplated Sn/Al, electroplatedCu/electroplated Ni/electroplated Sn/Rh, or electroplatedCu/electroplated Ni/electroplated Sn/Ag. Al and Rh are particularlysuitable for UV light of shorter wavelengths (e.g., UV-C, B). If Sn isapplied onto the lower side 14 f-2, a metal having a higher reflectancethan Sn (e.g., Al, Rh, or Ag) is not applied onto the lower side 14 f-2,in order to let Sn used for bonding with the bonding layer 14 b. Thus,PVD, instead of plating, is employed to prevent the formation of a metalhaving a higher reflectance (e.g., Al, Rh, or Ag) on the lower side 14f-2; (ii) after Sn is electroplated, a transparent oxide (e.g., SnO₂,SiO₂, or ZnO) can be deposited (e.g., by PVD) to protect Sn fromdiscoloration and degradation in quality; or (iii) after Sn iselectroplated, a transparent Sn oxide (SnO₂) film may be coated by O₂plasma treatment. Independently of the type of materials (e.g., Sn, Ni,Cu, etc.) used, the electroplating process, compared with theelectroless plating process, applies a more uniform and strongerelectrical energy, which in turn enables to form a conductive film ofuniform thickness and high density. In addition, the process time can beshortened. Therefore, it is preferable that Sn is utilized forelectroplating. Examples of materials for the bonding layer 14 b mayinclude, but without limitation, a soldering material such as Au—Sn,Ni—Sn, Au—Ni—Sn, Au—In, Pd—In, Cu—Sn, or Au—Cu—Sn, a paste material suchas Ag powder, Cu powder, or ESP (Epoxy Silicone Paste), or an adhesivematerial such as silicone or epoxy.

According to the present disclosure, the bottom portion 15 a may becomprised of a ceramic (e.g., sapphire (6.5 ppm), sintered Al₂O₃ (7ppm), sintered AlN (4.8 PPM), and sintered SiN_(x) (2.8 ppm)) substratethat has a thermal expansion coefficient not much different from that ofthe growth substrate 11 a (in case of a flip chip) or the supportsubstrate (not shown) (in case of a vertical chip) of the semiconductorlight emitting chip 11. For example, (i) in case of a flip chip (namely,if the sapphire growth substrate 11 a is retained or not removed),sapphire, sintered Al₂O₃, or sintered AlN is preferentially employed;(ii) in case of a vertical chip (namely, if the growth substrate 11 a isremoved and a growth substrate (e.g., MoCu (6.5 ppm)) is used instead),sapphire, Al₂O₃, or sintered AlN is again preferentially employed; and(iii) in another case of a vertical chip (namely, if the growthsubstrate 11 a is removed and a growth substrate (e.g., Si (2.3 ppm)) isused instead), sintered AlN or sintered SiN_(x) is preferentiallyemployed. With such a ceramic substrate as the bottom portion 15 a, itis possible to prevent separation of the electrodes 12 and 13 from theconductive parts 18 and 19 even when the semiconductor light emittingchip 11 is flip bonded, and to restrict thermal expansion of theconductive parts 18 and 19 as the ceramic substrate has a thermalexpansion coefficient that is essentially not too high (e.g., 3-7 ppm).Therefore, the semiconductor UV light emitting chip 11 of the presentdisclosure has advantages as follows: (i) any issue involved withdegradation of the mold 14 based on resins such as PPA, PCT, EMC or SMCcan be overcome; (ii) the electrodes 12 and 13 are not easily separatedby providing the bottom portion 15 a comprised of a ceramic substratethat has a thermal expansion coefficient not too high and not muchdifferent from that of the growth substrate 11 a (flip chip) or thesupport substrate (not shown) (vertical chip); (iii) the conductiveparts 18 and 19 can be stably anchored; and (iv) the reflective wall 14f has a matrix (e.g., thermoplastics or thermosetting plastics) suitablefor injection molding, and the reflective layer 14 g is formed by theLDS process. In this regard, it is important that the cavity 41 in thesemiconductor UV light emitting chip 11 has a slated reflective wall 14f. If the reflective wall 14 f is entirely made of metals, it is hard tomake it slanted or to adjust its slope. In this regard, the reflectivewall 14 f may be prepared by injection molding of a resin-based materialso that the slanted side 14 f-1 of a desired shape (circular,quadrangular, or polygonal) and angle can be obtained. However, theresin-based material is not usually applicable as it is. Additionally,or alternatively, a metal coating may be applied onto the resin-basedreflective wall 14 f, but the metal coating is unlikely to be stablyretained for an extended period of time (e.g., at least 10,000 hours).However, this is resolved by preparing the reflective layer 14 g usingthe LDS process, according to the present disclosure. In an alternativeto the reflective wall 14 f containing at least one LDS additive that isactivated by a laser beam and serves as a seed for electroless plating,it is also envisaged that the reflective wall 14 f is comprised of a Sisemiconductor 100 because the Si semiconductor 100 having crystal planesare (i) better adapted to adjustment of the slanted side 14 f-1 throughKOH wet etching and/or dry etching, and (ii) excellent in adhering to ametal (e.g., Al or Ag) of the reflective layer 14 g. Additionally, oralternatively, the reflective wall 14 f may be made of any materialwithout particular limitations, provided that these two conditions (i)and (ii) described above are satisfied. If the reflective wall 14 f iscomprised of the Si semiconductor 100, the bottom portion 15 a made ofSiN_(x) (2.8 ppm) or AlN (4.8 ppm), rather than sapphire (6.5 ppm) andAl₂O₃ (7 ppm) is preferentially used, taking a thermal expansioncoefficient of the Si semiconductor (2.5 ppm) into consideration.

FIG. 13 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Patent Application Publication No.2014/0367718. Here, the semiconductor light emitting device includes asemiconductor light emitting chip 411 and two metal bodies 414 a and 414b. These two metal bodies 414 a and 414 b are electrically insulated byan insulating layer 415. Each of the metal bodies 414 a and 414 b has acavity 441 and a holding portion 440. A window 460 is held on theholding portion 440 using an adhesive 461. Additionally, oralternatively, a heat dissipation metal layer 421 is provided. Althoughthese metal bodies 414 a and 414 b may be useful for increasing thereflectance of UV light, it is not easy to form a slanted side 14 f-1 onthem as mentioned earlier, and a related machining process is pricey.Moreover, their high thermal expansion coefficients (19-23 ppm) alsomake it difficult to keep them from being separated from thesemiconductor light emitting chip 411.

FIG. 14 illustrates an exemplary embodiment of a semiconductor lightemitting device disclosed in U.S. Pat. No. 8,106,584. Here, thesemiconductor light emitting device includes a semiconductor lightemitting chip 511, a reflective wall 514, a bottom portion 515, a cavity541, a light transmitting part 561, a first window 562, and a secondwindow 563. The reflective wall 514 is secured on the bottom portion 515and has a light-reflecting inner surface slanted upwards, surroundingthe semiconductor light emitting chip 511. The reflective wall 514 maybe made of a metal (e.g., Al, or an alloy of Fe—Ne—Co), sintered Al₂O₃,an epoxy resin, or the like. The bottom portion 515 has a wire conductor(not shown) for supplying current to the semiconductor light emittingchip 511, covering from the upper side to the lower or lateral sides ofthe bottom portion 515. The bottom portion 515 may be made of sinteredAl₂O₃, sintered AlN, sintered mullite, glass ceramics, an epoxy resin, ametal, or the like. Although this semiconductor light emitting device inFIG. 14 may be very similar to the semiconductor light emitting deviceaccording to the present disclosure in that its bottom portion 515 canbe comprised of sintered Al₂O₃ or sintered AlN, it does not have theconfiguration and slanted inner surface of the reflective wall 514 andenhanced long-term reliability related qualities including reflectanceand durability of the inner surface, as found in the present disclosure.For example, the semiconductor light emitting device shown in FIG. 14has the bottom portion 515 made of sintered Al₂O₃ or sintered AlN andthe reflective wall 514 made of an epoxy resin, as claimed.Unfortunately, this conventional reflective wall 514 made of an epoxyresin not only absorbs light in the UV wavelength range, but it is alsosubjected to UV-induced degradation due to aging. To prevent this, theslanted side of the reflective wall 514 could be coated with areflective layer (Ag or Al), but hydrophobic interactions (physicalcontacts), not hydrophilic interactions (chemical contacts), between theepoxy resin of the reflective wall 514 and the reflective layer coatedon the slanted side of the reflective wall 514 may lead to weakerbonding, failing to compromise degradation in long-term reliabilityrelated qualities. In contrast, according to the present disclosure, thereflective wall 14 f made of a resin suitable for LDS and the reflectivelayer (Ag or Al) coating provides hydrophilic interactions thatdemonstrate strong bonding strength between materials, which in turnensures long-term reliability.

Further, the present disclosure provides means (using metallic bonding)for improving the overall waterproof function of the semiconductor lightemitting device, by introducing the reflective layer 14 g made of ametal demonstrating strong bonding strength towards the reflective wall14 f made of a resin suitable for LDS or comprised of a Si semiconductor100. In particular, in case of the reflective wall 14 f made of a resinsuitable for LDS, the reflective layer 14 g is formed on the slantedside 14 f-1 of the reflective wall, and the lower and upper sides 14 f-2and 14 f-3 of the reflective wall 14 f undergo laser irradiationfollowed by electroless plating for metal treatment and are coupled withthe bottom portion 15 a and the window 60 by eutectic bonding orsoldering 14 b, 60 a, thereby improving the waterproof function of thedevice. In case of the reflective wall 14 f comprised of a Sisemiconductor 100, the Si semiconductor undergoes metal treatment andthe resulting, metal-treated Si semiconductor 100 is coupled with thebottom portion 15 a and the window 60 by eutectic bonding or soldering14 b, 60 a, thereby improving the waterproof function of the device.More preferably, the electrodes 12 and 13 of the semiconductor lightemitting chip 11 and the conductive parts 18 and 19 of the bottomportion 15 a are coupled by Au 80%-Sn 20% eutectic bonding at arelatively high temperature (300° C. or lower). After that, the bottomportion 15 a and the reflective wall 14 f undergo high-temperaturesoldering (280° C. or lower) using the soldering material 14 b, and thewindow 60 and the reflective wall 14 f undergo low-temperature soldering(260° C. or lower) using the soldering material 60 a. In result, thesemiconductor light emitting chip 11 is not separated during themanufacturing process, and the overall waterproof function of thesemiconductor light emitting device can be improved. In an alternative,the reflective wall 14 f and the bottom portion 15 a can be coupled bymetallic bonding, after the reflective wall 14 f and the window 60 arefirst coupled.

The application of the LDS process on an injection molded article usedas the reflective wall 14 f involves employing an LDS mold matrix resin(thermosetting plastics or thermoplastics) that contains LDS additives(e.g., organic metal compounds or metal particles), in which aninjection molded article prepared or molded with such a mold matrixresin is irradiated on its surface with a laser beam so that the surfacemay have a high roughness and be electrically activated, and thelaser-irradiated region of the surface undergoes electroless plating,producing a conductive material thereon. The LDS mold matrix resin canbe thermoplastics (e.g., polyphthalamide (PPA) or polycyclohexylenedimethylene terephthalate (PCT)) or thermosetting plastics (e.g., epoxymold compounds (EMC) or silicone molding compounds (SMC)). Specificexamples of the LDS mold matrix resin may include, but withoutlimitation, ABS (acrylonitrile-butadiene-styrene), PC (polycarbonate),PET (polyethylene terephthalate), PA (polyamides), PPA(polyphthalamide), PBT (polybutylene terephthalate), COP (cyclic olefinecopolymer), PPE (polyphenylene ether), LCP (liquid crystal polymer), PEI(polyetherimide), PEEK (poly ether ether ketone), and the like. The LDSadditives include a blend of a first additive that is a primarycomponent and serves as a seed in the LDS mold matrix resin uponlaser-beam irradiation, and additionally, a second additive that is usedto improve heat dissipation performance. In general, the first additiveincludes at least one of:

Pd-based heavy metal complexes and metal oxides, metal oxide-coatedfillers, CuO.Cr₂O₃ spinel, copper salts, copper hydroxyphosphate, copperphosphate, cuprous thiocyanate, spinel-based metal oxides, CuO.Cr₂O₃,organometallic complexes, antimony (Sb) doped Sn oxide, or metal oxidescontaining Cu, Zn, Sn, Mg, Al, Au, Ag, Ni, Cr, Fe, V, Co, or Mn. Thesecond additive, which is one of functional additives, used to improveheat dissipation performance includes at least one of: AlN, AlC, Al₂O₃,AlON, BN, MgSiN₂, Si₃N₄, SiC, graphite, graphene, carbon fiber, ZnO,CaO, or MgO.

FIG. 15 illustrates another exemplary embodiment of a semiconductorlight emitting device according to the present disclosure. Here, thestepped sides 14 f-21 and 14 f-22 are formed on the upper side 14 f-3 ofthe reflective wall 14 f to be coupled with the window 60. After thestepped sides 14 f-21 and 14 f-22 undergoes metal treatment through theLDS process, the window 60 and the reflective wall 14 f are coupled bymetallic bonding such that more stable coupling may be achieved betweenthem.

FIGS. 16 and 17 illustrate another exemplary embodiment of asemiconductor light emitting device according to the present disclosure.FIG. 16 shows some problems that may occur as the semiconductor lightemitting device of FIG. 4 is coupled to a power supply board P (e.g., aPCB or sub-mount). As discussed previously, the semiconductor lightemitting device of FIG. 4 has the through holes 16 and 17 which are notfilled with the conductive parts 18 and 19, while the semiconductorlight emitting device of FIG. 6 has the through holes 16 and 17 whichare filled with the conductive parts 18 and 19. As shown in FIG. 16A,the through holes 16 and 17 are blocked by the semiconductor lightemitting chip 11 on the upper side 15 a of the bottom portion 15. If asolder S is used for coupling, an air gap A may be created as the solderS is introduced into the through holes 16 and 17 along the conductiveparts 18 and 19, as shown in FIG. 16B. The air gap A not only interfereswith proceeding of the solder S towards the top of the through holes 16and 17, but its irregular shape also interferes with stable electricalcoupling of the semiconductor light emitting device to the power supplyboard P. To resolve these issues, according to the present disclosure,the through holes 16 and 17 are provided with the conductive parts 18and 19, as well as air gap-preventing materials 18 b and 19 b. The typeof the air gap-preventing materials 18 b and 19 b is not particularlylimited, provided that the materials can successfully suppress theformation of an air gap. For instance, they can be a conductive materialsuch as an Ag- and/or Cu-based paste discussed in FIG. 6. Preferably,though, they can be a non-conductive material that is not blended withthe solder S (e.g., white silicone or a liquid polymer resin), tominimize the intrusion the solder S into the through holes 16 and 17.Therefore, it is preferable to fill the through holes 16 and 17 with theair gap-preventing materials 18 b and 19 b all the way down to thebottom ends (the lower side 15 b of the bottom portion 15).Alternatively, it is also possible that the through holes 16 and 17 arepartly filled. The air gap-preventing materials 18 b and 19 b may beprovided to the through holes 16 and 17 before or after thesemiconductor light emitting chip 11 is coupled with the conductiveparts 18 and 19. If needed, i.e., if the conductive parts 18 and 18 arenot too thick (e.g., 5 μm or less), reinforcing conductors 18 c and 19 c(e.g., Cu, Ag, Au, Ni, or Pd) may be additionally provided by PVD suchas sputtering or e-beam evaporation. Although it is possible to form thereinforcing conductors 18 c and 19 c by plating, PVD is preferredbecause it provides better electrical and thermal conductivities thanthe plating and because it allows the formation of the reinforcingconductors 18 c and 19 c only on the lower side 15 b of the bottomportion 15. Preferably, the through holes 16 and 17 may have a graduallyincreasing width from the upper side 15 a to lower side 15 b of thebottom portion 15 (which can be achieved during injection molding of thethrough holes 16 and 17 in the mold, or by irradiating a laser beam forLDS onto the lower side 15 b of the bottom portion 15). In this manner,the reinforcing conductors 18 c and 19 c as well as the airgap-preventing materials 18 b and 19 b can be stably accommodated in thethrough holes 16 and 17. The air gap-preventing materials 18 b and 19 bcan be prepared by screen printing using a stencil shadow mask, or bydispensing using a nozzle for precise dispensing. If the through holes16 and 17 are via-filled with a solder S containing an acid flux (thatis, the major component of the flux is an acid) and subsequentlysubjected to a reflow process for heat treatment, gases are produced,and irregular air gaps are created by the gases. In contrast, accordingto the present disclosure, the through holes 16 and 17 are via-filledwith white silicone, a liquid polymer resin, and a conductive materialsuch as an Ag- and/or Cu-based paste, and the solder S is then subjectedto a reflow process. Thus, it is practically impossible for gasesproduced by the solder S to enter into the through holes 16 and 17 andcreate irregular air gaps. Again, the air gap-preventing materials 18 band 19 b may be prepared before or after the semiconductor lightemitting chip 11 is coupled with the conductive parts 18 and 19. Whenthe air gap-preventing materials 18 b and 19 b are prepared before thesemiconductor light emitting chip 11 is coupled with the conductiveparts 18 and 19, it is preferable that the through holes 16 and 17 areblocked in advance with a shadow mask or a protective layer from theside of the cavity prior to the preparation of the air gap-preventingmaterials 18 b and 19 b.

Set out below are a series of clauses that disclose features of furtherexemplary embodiments of the present disclosure, which may be claimed.

(1) A semiconductor light emitting device, comprising: a semiconductorlight emitting chip having electrodes; a mold, which has a first surfaceroughness and includes a bottom portion where the semiconductor lightemitting chip is arranged and through holes formed in the bottomportion, with the through holes being comprised of a surface having asecond surface roughness different from the first surface roughness,wherein at least one side of the mold facing the semiconductor lightemitting chip is made of a material capable of reflecting at least 95%of light emitted by the semiconductor light emitting chip; andconductive parts provided in the through holes for electricalcommunication with the electrodes.

(2) There is also provided, the semiconductor light emitting device ofclause (1) wherein: a metal is exposed on the surface of the throughholes to serve as a seed for forming the conductive parts

(3) There is also provided, the semiconductor light emitting device ofclause (2) further comprising: a heat dissipation metal layer, which isformed on a lower side of the bottom portion and has a patterncorresponding to a design pattern on the lower side of the bottomportion, wherein the lower side of the bottom portion has a thirdsurface roughness higher than the first surface roughness.

(4) There is also provided, the semiconductor light emitting device ofclause (3) wherein: the heat dissipation metal layer is connected withthe conductive parts.

(5) There is also provided, the semiconductor light emitting device ofclause (3) further comprising: upper metal layers, which are formed onthe upper side of the bottom portion, sticking out of the through holes,and electrically bonded with the electrodes and conductive parts.

(6) There is also provided, the semiconductor light emitting device ofclause (1) wherein: the conductive parts are formed by electrolessplating, and the mold contains at least one LDS additive that isactivated by a laser beam and serves as a seed for the electrolessplating.

(7) There is also provided, the semiconductor light emitting device ofclause (1) wherein: the conductive parts are formed by electrolessplating, and the mold contains a first additive that is activated by alaser beam and serves as a seed for the electroless plating and a secondadditive that is activated by a laser beam and serves as a seed for theelectroless plating, with the second additive having better heatdissipation performance than the first additive against heat generatedfrom the semiconductor light emitting chip.

(8) There is also provided, the semiconductor light emitting device ofclause (1) wherein: the conductive parts are formed by electrolessplating, and the mold contains a first additive that is activated by alaser beam and serves as a seed for the electroless plating and a thirdadditive that has a higher reflectance than the first additive for lightemitted by the semiconductor light emitting chip.

(9) There is also provided, the semiconductor light emitting device ofclause (7) or (8) wherein: the first additive comprises at least oneselected from the group consisting of: Pd-based heavy metal complexesand metal oxides, metal oxide-coated fillers, CuO.Cr₂O₃ spinel, coppersalts, copper hydroxyphosphate, copper phosphate, cuprous thiocyanate,spinel-based metal oxides, CuO.Cr₂O₃, organometallic complexes, antimony(Sb) doped Sn oxide, and metal oxides containing Cu, Zn, Sn, Mg, Al, Au,Ag, Ni, Cr, Fe, V, Co, or Mn.

(10) There is also provided, the semiconductor light emitting device ofclause (7) wherein: the second additive comprises at least one selectedfrom the group consisting of: AlN, AlC, Al₂O₃, AlON, BN, MgSiN₂, Si₃N₄,SiC, graphite, graphene, carbon fiber, ZnO, CaO, or MgO.

(11) There is also provided, the semiconductor light emitting device ofclause (8) wherein: the third additive comprises at least one selectedfrom the group consisting of: TiO₂, ZnO, BaS, and CaCO₃.

(12) There is also provided, the semiconductor light emitting device ofclause (1) wherein: the mold is activated by a laser beam and serves asa seed for forming the conductive parts, with the mold containing anadditive that reflects light emitted by the semiconductor light emittingchip, in an amount of at least 50 wt. %.

(13) There is also provided, the semiconductor light emitting device ofclause (12) wherein: the additive is TiO₂.

(14) There is also provided, the semiconductor light emitting device ofclause (8) wherein: the first additive is contained in a greater amountin the lower region of the mold than that in the upper region of themold.

(15) There is also provided, the semiconductor light emitting device ofclause (6) wherein: the mold comprises a reflective layer on a sidefacing the semiconductor light emitting chip to reflect light emitted bythe semiconductor light emitting chip.

(16) A method for manufacturing a semiconductor light emitting deviceincluding a semiconductor light emitting chip having electrodes, a moldwhich has a bottom portion where the semiconductor light emitting chipis arranged and through holes formed in the bottom portion, andconductive parts provided in the through holes for electricalcommunication with the electrodes, the method comprising: preparing alead frame which has one or more molds and an anti-plating layer formedon a region exposed from the molds; forming conductive parts in each ofthe molds and electrically communicating the conductive parts with theelectrodes of the semiconductor light emitting chip; and cutting out thelead frame to obtain individual semiconductor light emitting devices.

(17) There is also provided, the method for manufacturing asemiconductor light emitting device of clause (16) wherein: the throughholes are formed during preparing the lead frame, and subsequently alaser beam is irradiated to the through holes to provide seeds forforming the conductive parts.

(18) There is also provided, the method for manufacturing asemiconductor light emitting device of clause (16) wherein: the throughholes are formed by laser drilling.

(19) There is also provided, the method for manufacturing asemiconductor light emitting device of clause (16) wherein: theconductive parts are formed by electroless plating.

(20) A semiconductor light emitting device that contains a nanoscale(nano-dimensioned) metal or metal oxide particle material showing a lowabsorption and high transparency for visible light in lieu of a first,second, and/or third additive, and a method for manufacturing thesemiconductor light emitting device.

(21) A semiconductor light emitting device, comprising: a semiconductorUV light emitting chip having electrodes; a bottom portion where thesemiconductor light emitting chip is arranged, with the bottom portionbeing made of a ceramic material and including conductive parts forelectrical communication with the electrodes; and a reflective walldefining a cavity to accommodate the semiconductor light emitting chiptherein, with the reflective wall being made of a non-metal andincluding a slanted side that reflects UV light and a metal reflectivelayer formed on the slanted side.

(22) There is also provided, the semiconductor light emitting device ofclause (21) wherein: the reflective wall comprises a blend of an LDSmold matrix resin and LDS additives.

(23) There is also provided, the semiconductor light emitting device ofclause (21) wherein: the LDS additives includes a first additive as aprimary component, and/or additionally, a second additive used forimproving heat dissipation performance.

(24) There is also provided, the semiconductor light emitting device ofclause (21) wherein: the reflective wall is comprised of a siliconsemiconductor 100 having crystal planes.

(25) There is also provided, the semiconductor light emitting device ofclause (21) wherein: the reflective wall and the bottom portion arecoupled without a bonding layer in-between.

(26) There is also provided, the semiconductor light emitting device ofclause (21) wherein: the reflective wall and the bottom portion arecoupled with a metallic bonding layer.

(27) There is also provided, the semiconductor light emitting device ofclause (21) further comprising: a window arranged on the reflectivewall, wherein the reflective wall and the window are coupled by metallicbonding.

(28) A semiconductor light emitting device adapted to be coupled to apower supply board by a solder, comprising: a semiconductor lightemitting chip having electrodes; a mold, which includes a bottom portionwhere the semiconductor light emitting chip is arranged and throughholes having a surface roughness higher than that of an upper side ofthe bottom portion; hollow conductive parts provided in the throughholes for electrical communication with the electrodes; and an airgap-preventing material provided in each of the through holes forpreventing the creation of air gaps as the solder enters into thethrough holes along the conductive parts, wherein the upper side of thebottom portion is not covered by upper metallic layers 18 a and 19 a butexposed into a cavity.

(29) There is also provided, the semiconductor light emitting device ofclause (28) wherein: the air gap-preventing material comprises anon-conductive material.

(30) There is also provided, the semiconductor light emitting device ofclause (28) further comprising: a heat dissipation metal layer 21 formedon a lower side of the bottom portion, with the heat dissipation metallayer being connected to the conductive parts and coupled with thesolder, wherein the lower side of the bottom portion has a surfaceroughness higher than that of the upper side of the bottom portion.

(31) There is also provided, the semiconductor light emitting device ofclause (28) wherein: the through holes are wider on the lower side ofthe bottom portion than on the upper side of the bottom portion.

(32) There is also provided, the semiconductor light emitting device ofclause (28) further comprising: reinforcing conductors between theconductive parts and the air gap-preventing material.

An exemplary embodiment of a semiconductor light emitting deviceaccording to the present disclosure is configured to prevent light leaksdownwards of the mold and features more securely anchored conductivelayers.

Another exemplary embodiment of a semiconductor light emitting deviceaccording to the present disclosure benefits from the LDS processapplied to the reflective wall, and the application of a ceramicsubstrate having a low thermal expansion coefficient allows theconductive layers of the device to be stably anchored on the bottomportion.

Another exemplary embodiment of a semiconductor light emitting deviceaccording to the present disclosure is adapted to suppress the formationof air gaps caused by the solder inside the through holes duringsoldering.

1. A semiconductor light emitting device, comprising: a semiconductor light emitting chip having electrodes; a mold, which has a first surface roughness and includes a bottom portion where the semiconductor light emitting chip is arranged and through holes formed in the bottom portion, with the through holes being comprised of a surface having a second surface roughness different from the first surface roughness, wherein at least one side of the mold facing the semiconductor light emitting chip is made of a material capable of reflecting at least 95% of light emitted by the semiconductor light emitting chip; and conductive parts provided in the through holes for electrical communication with the electrodes.
 2. The semiconductor light emitting device of claim 1, wherein a metal is exposed on the surface of the through holes to serve as a seed for forming the conductive parts.
 3. The semiconductor light emitting device of claim 2, further comprising: a heat dissipation metal layer, which is formed on a lower side of the bottom portion and has a pattern corresponding to a design pattern on the lower side of the bottom portion, wherein the lower side of the bottom portion has a third surface roughness higher than the first surface roughness.
 4. The semiconductor light emitting device of claim 3, wherein the heat dissipation metal layer is connected with the conductive parts.
 5. The semiconductor light emitting device of claim 3, further comprising: upper metal layers, which are formed on the upper side of the bottom portion, sticking out of the through holes, and electrically bonded with the electrodes and conductive parts.
 6. The semiconductor light emitting device of claim 1, wherein the conductive parts are formed by electroless plating, and the mold contains at least one LDS additive that is activated by a laser beam and serves as a seed for the electroless plating.
 7. The semiconductor light emitting device of claim 1, wherein the conductive parts are formed by electroless plating, and the mold contains a first additive that is activated by a laser beam and serves as a seed for the electroless plating and a second additive that is activated by a laser beam and serves as a seed for the electroless plating, with the second additive having better heat dissipation performance than the first additive against heat generated from the semiconductor light emitting chip.
 8. The semiconductor light emitting device of claim 1, wherein the conductive parts are formed by electroless plating, and the mold contains a first additive that is activated by a laser beam and serves as a seed for the electroless plating and a third additive that has a higher reflectance than the first additive for light emitted by the semiconductor light emitting chip.
 9. The semiconductor light emitting device of claim 7, wherein the first additive comprises at least one selected from the group consisting of: Pd-based heavy metal complexes and metal oxides, metal oxide-coated fillers, CuO.Cr₂O₃ spinel, copper salts, copper hydroxyphosphate, copper phosphate, cuprous thiocyanate, spinel-based metal oxides, CuO.Cr₂O₃, organometallic complexes, antimony (Sb) doped Sn oxide, and metal oxides containing Cu, Zn, Sn, Mg, Al, Au, Ag, Ni, Cr, Fe, V, Co, or Mn.
 10. The semiconductor light emitting device of claim 7, wherein the second additive comprises at least one selected from the group consisting of: AlN, AlC, Al₂O₃, AlON, BN, MgSiN₂, Si₃N₄, SiC, graphite, graphene, carbon fiber, ZnO, CaO, or MgO.
 11. The semiconductor light emitting device of claim 8, wherein the third additive comprises at least one selected from the group consisting of: TiO₂, ZnO, BaS, and CaCO₃.
 12. The semiconductor light emitting device of claim 1, wherein the mold is activated by a laser beam and serves as a seed for forming the conductive parts, with the mold containing an additive that reflects light emitted by the semiconductor light emitting chip, in an amount of at least 50 wt. %.
 13. The semiconductor light emitting device of claim 12, wherein the additive is TiO₂.
 14. The semiconductor light emitting device of claim 8, wherein the first additive is contained in a greater amount in the lower region of the mold than that in the upper region of the mold.
 15. The semiconductor light emitting device of claim 6, wherein the mold comprises a reflective layer on a side facing the semiconductor light emitting chip to reflect light emitted by the semiconductor light emitting chip.
 16. The semiconductor light emitting device of claim 8, wherein the first additive comprises at least one selected from the group consisting of: Pd-based heavy metal complexes and metal oxides, metal oxide-coated fillers, CuO.Cr₂O₃ spinel, copper salts, copper hydroxyphosphate, copper phosphate, cuprous thiocyanate, spinel-based metal oxides, CuO.Cr₂O₃, organometallic complexes, antimony (Sb) doped Sn oxide, and metal oxides containing Cu, Zn, Sn, Mg, Al, Au, Ag, Ni, Cr, Fe, V, Co, or Mn. 